Ceramic Arts Network https://ceramicartsnetwork.org Thu, 17 Aug 2017 15:18:15 +0000 en-US hourly 1 https://wordpress.org/?v=4.8 Two Ways to Sculpt Eyes on a Ceramic Figure https://ceramicartsnetwork.org/daily/ceramic-art-and-artists/ceramic-sculpture/two-ways-to-sculpt-eyes-on-a-ceramic-figure/ https://ceramicartsnetwork.org/daily/ceramic-art-and-artists/ceramic-sculpture/two-ways-to-sculpt-eyes-on-a-ceramic-figure/#respond Thu, 17 Aug 2017 12:00:58 +0000 https://ceramicartsnetwork.org/daily/ceramic-art-and-artists/ceramic-sculpture/two-ways-to-sculpt-eyes-on-a-ceramic-figure/ When sculpting the human head, Melisa Cadell starts with a thick cylinder so she is able to add volume and life both from the inside and outside. In today’s post,  

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Sculpting eyes

When sculpting the human head, Melisa Cadell starts with a thick cylinder so she is able to add volume and life both from the inside and outside. In this post, an excerpt from her video Figure Sculpting in Clay, Melisa demonstrates two ways to approach the eyes when sculpting in this manner. – Jennifer Poellot Harnetty, editor.



This clip was excerpted from Figure Sculpting in Clay, which is available in the Ceramic Arts Shop!


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To learn more about Melisa Cadell or to see more images of her work, please visit www.melisacadell.com.

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Raku on the Walls: How to Make a Raku Mural https://ceramicartsnetwork.org/daily/ceramic-glaze-recipes/low-fire-glaze-recipes/raku-on-the-walls-how-to-make-a-raku-mural/ https://ceramicartsnetwork.org/daily/ceramic-glaze-recipes/low-fire-glaze-recipes/raku-on-the-walls-how-to-make-a-raku-mural/#comments Thu, 17 Aug 2017 09:40:03 +0000 https://ceramicartsnetwork.org/daily/ceramic-glaze-recipes/low-fire-glaze-recipes/raku-on-the-walls-how-to-make-a-raku-mural/ If you have ever done raku firing, you are probably aware that the raku firing process should not be used for pots that are intended to serve food. The rapid  

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If you have ever done raku firing, you are probably aware that the raku firing process should not be used for pots that are intended to serve food. The rapid firing, removal of the ware at the red-heat stage, and subsequent post-firing all contribute to surfaces that remain porous after firing. So it is best for decorative pots or sculpture. If you are looking for another application for raku, today’s post just might be for you.

In this post,  Barbara VanSickle shows you how making a raku mural gives you a chance to explore making art for the walls.  – Jennifer Poellot Harnetty, editor.


India Blue Peacock, 48 inches in.

India Blue Peacock, 48 inches in.

The idea of creating raku murals happened quite naturally. A few years ago I was fortunate enough to be asked to create a retirement gift for a dear friend and former colleague. I needed to design something very special. I knew that he was partial to raku surfaces. During visits to his home, I was struck by its impressive open-concept architecture with the tall, wide wall spaces. The more I thought about what to make, the clearer it became: a raku mural.

The problem was I had no idea on how to proceed. My experience with raku was limited and, although I had previously created some murals for a school installation with children, I’d never attempted anything like this. The school project gave me some of the technical knowledge and experience of creating, drying and mounting the clay tiles but I needed inspiration for the subject matter.

I turned to my own environment and my love of Art Nouveau stained glass to come up with the design for “India Blue Peacock.” Two doors down the road from me lives a family that raises India Blues. I hear the peacock calls all through the days from early spring to late fall. Linking the peacock with the Art Nouveau stained-glass look was quite natural.

Since making this first mural, I have continued to look to my own experiences and environment for inspiration.

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Click images to enlarge!

Prepare Paper Template

Begin a mural by making a series of small drawings. Whatever your inspiration, remember that simplified edges work best (as in stained glass) and that some areas naturally lend themselves to being cut into sections. If you have areas that would be too large for one tile, plan how you’ll adapt your work by adding divisions in the tiles that add to the overall design. Enlarge the drawing to actual size, then use a marker to highlight the lines. On larger projects, you’ll need to cut your plan into smaller pieces. If so, number each piece on the back to make it easier to reassemble later (figure 1).

Prepare the Slab

Roll out a slab to a thickness of approximately 3/8 inch on a textured material, such as rubber shelf liner or placemats. The textured rubber material provides a perfect backing for the tile, which helps prevent warping during drying and firing. It also makes the slabs easy to carry without distorting (figure 2).

figs4-5Remove any unwanted marks with a rib and rolling pin, being sure to roll the slab no thinner than 1/3 inch. Thinner tiles are more likely to warp during drying and firing (figure 3). Peel off the rubber backing, then join slabs together as needed (figure 4). Place the slabs on a flat surface, and cover it with plastic for about a day.

Transfer the Design

Lay the paper pattern on the slab, then using a blunt tool, such as the dull end of a wooden skewer, trace over the marker lines. When the template is removed, you will be able to use the incised lines as guides for adding any relief or textures. Trim the edges of your panel using a straightedge and a sharp, dry knife, then cut the panel into individual tiles (figure 5).

Create the Pieces

Arrange your cut tiles on a large board or table to form your mural and add any relief or impressed designs. Once you’ve completed all the additions, cut through any pieces that overlap from tile to tile. Clean up and smooth all edges.

Drying process

Cover the entire mural with plastic, and place sandbags strategically to keep the pieces as flat as possible during the drying phase. Tip: I make sandbags by cutting up old sheets into 12-inch squares, then scoop sand onto them, bring the edges up and fasten them with rubber bands. They are a great tool to have around the studio (figure 6). Check on the mural daily as warping can be reduced by relocating the sandbags if you catch it right away. Once leather hard, turn the tiles over and recover with plastic to allow them to dry slowly (about a week in my studio). Remove the plastic, turn the tiles right side up, and give the work at least another day to dry before bisque firing.

Glazing

Reassemble all the pieces to form the mural before glazing. This makes it much ea
sier to apply the glazes accurately. If you’re masking any areas, apply your tape or resist material. I prefer to use black graphic tape as it provides excellent contrast, and can easily be rearranged without leaving residue on the bisqued tiles. It also creates perfectly straight lines (figure 7). Apply glazes according to your original drawings. I prefer to brush them on by completing all of one glaze color at a time on the entire mural before moving to the next glaze (figure 8).

 Raku

I fire my mural pieces in a raku kiln (figure 9). Due to the extreme range of reduction effects that influence the glaze surface and color development, try to fire tiles that will be side by side in the mural in the same load. If possible place them in the same reduction chamber together. Use a pyrometer and time each fire to get the greatest consistency between loads, and try to fire under the same conditions if your work will take longer than a day. This process takes considerable planning but the results are well worth the effort. If you get too much or too little reduction on a particular piece, remember that you can always refire.

Assemble the mural

Reassemble the mural (figure 10) and measure the finished height and width. This is the base measurement for your mounting board. Where and how your work is hung determines the type of material for mounting. If you’re working on a project any larger that 8 square feet, use plywood. For smaller murals, I recommend 5/8-inch-thick medium density fiber board (MDF) as it is lighter, though on larger murals it can warp.

figs11-12For a mural the size made here, mark the MDF board roughly three-fourths of the way up from the bottom edge and drill ¼-inch holes 2 inches in from either side. Countersink the holes on the front of the board deep enough for a ¼-inch nut to be flush with the face. Drill two large diameter washers to accept the hanging wire and bend them slightly outward. Attach the washers to the back of the board through the ¼-inch bolt head and tighten (figure 11).

 figs13-15Prime the MDF and, when thoroughly dry, apply paint (I prefer matt black). Allow the paint to dry completely for 24 hours, then spread a good quality construction glue to the mounting board, keeping it off anywhere that will show when done (figure 12). Beginning at the bottom, apply the glue to the back of the tiles, one or two at a time, and assemble. The glue dries very fast, so you’ll need to work quickly (figure 13).
“White Pines,” 24 inches in height.

“White Pines,” 24 inches in height.

When it is completely dry (at least 8 hours), grout the mural. Remember in your planning that grout comes in many colors so it can further enhance the final project. Follow the manufacturer’s instructions. Once the grout begins to thicken, pour it on the mural paying particular attention to the small spaces between each tile (figure 14). Gradually remove the extra grout using a damp sponge, changing the water frequently (figure 15). Allow to dry.

Thread heavy duty picture wire through the holes in the washers and adjust the length appropriately.

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Artist Q&A: Meet Davie Reneau https://ceramicartsnetwork.org/daily/ceramic-art-and-artists/ceramic-artists/artist-qa-meet-davie-reneau/ https://ceramicartsnetwork.org/daily/ceramic-art-and-artists/ceramic-artists/artist-qa-meet-davie-reneau/#comments Thu, 17 Aug 2017 09:00:27 +0000 https://ceramicartsnetwork.org/daily/ceramic-art-and-artists/ceramic-artists/artist-qa-meet-davie-reneau/ Ceramics Monthly: Do your surroundings in Kentucky and the hard physical labor of wood firing influence the work you make?

Davie Reneau: Those two things are primary influences for me. I  

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Ceramics Monthly: Do your surroundings in Kentucky and the hard physical labor of wood firing influence the work you make?

Photo: Azucena Trejo Williams.

Davie Reneau: Those two things are primary influences for me. I live in one of the most beautiful places on Earth; visually there is nothing but inspiration. Voluptuous rolling hills, textures of plowed ground, and raked hay greatly influence the volume and surfaces of my pots.

Working on family farms as a child provided me with an intimate interaction with the landscape in the cyclical nature of preparing the ground, planting, then maintaining gardens, tobacco, and hay. Harvesting crops mimics the cycle of making pots and firing a wood kiln.

My dad and grandmother taught me how to work hard and find comfort, pleasure, and satisfaction in that hard work. Being dirty, sweaty, and tired at the end of a day of firing reminds me of the end of a day spent cutting tobacco and throwing hay bales into a wagon. Looking at my daily accomplishments, whether it’s an acre of tobacco cut or a good stack of wood split, always makes me happy.

CM: What decisions are involved in creating forms and surfaces so that they are simultaneously structured and soft?

DR: It’s more intuition than anything; these decisions are formed by years of experiencing the process. The clay and the wheel revealing things to me and I keep open minded in accepting of the interaction.

I think the hardest thing to overcome when first making pots is envisioning and drawing a specific form to make and rigidly refusing to accept anything else if something unexpected happens while on the wheel. For example, I always had difficulty getting a teapot spout on at the correct angle. My spouts looked stiff and static compared to the organic quality of the pot. One day I was throwing a ware board of spouts and I dropped one on the wheel head. Before throwing it out, I realized it kicked back to exactly the right angle, and was much softer than before. I now tap spouts on the wheel head as I take them off.

I facet everything wet on the wheel rather than at the leather hard stage. Some forms are softened when the centrifugal force of the wheel direction causes movement of the lines. In other forms, specifically teapots and belly vases, I want to preserve the integrity of the vertical lines because they are cut in four planes. I kick the wheel in the opposite direction to counteract the centrifugal force. To soften and shape these forms, I push out from the inside, accentuating the hips and belly on the vases. With the teapots, I push out at the top of the plane where the spout attaches and at the bottom where the handle attaches. This kills the symmetry and works with the fact I cut the top of the pot at an angle with the lowest point at the handle and the highest at the spout.

I want my pots to be functional and sculptural. The intimate connection between maker and user is important; however, I’m not offended when collectors buy my work, even though it will never be used. Visually it can still exist as a sculpture. Someday I might do some purely sculptural work, but I will always make pots designed for daily use. It is who I am.

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How to Clean Kiln Shelves, Mix Kiln Wash, and Apply Kiln Wash https://ceramicartsnetwork.org/daily/firing-techniques/how-to-clean-kiln-shelves-mix-kiln-wash-and-apply-kiln-wash/ https://ceramicartsnetwork.org/daily/firing-techniques/how-to-clean-kiln-shelves-mix-kiln-wash-and-apply-kiln-wash/#respond Thu, 17 Aug 2017 07:00:36 +0000 https://ceramicartsnetwork.org/daily/article/how-to-clean-kiln-shelves-mix-kiln-wash-and-apply-kiln-wash/ Kiln shelf maintenance is a much hated but very necessary part of having a kiln. Neglected kiln shelves can result in flakes of kiln wash landing smack dab in the  

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Kiln shelf maintenance is a much hated but very necessary part of having a kiln. Neglected kiln shelves can result in flakes of kiln wash landing smack dab in the middle of a beautiful glaze surface, or pots inadvertently sticking to shelves where a glaze drip once landed. So it’s best to stay on top of cleaning your kiln shelves and to know how to apply kiln wash.

In today’s post, an excerpt from Clay: A Studio Handbook, Vince Pitelka gives some tips on scraping kiln shelves, mixing kiln wash, and shares a couple of kiln wash recipes. – Jennifer Poellot Harnetty, editor.


Shelf Scraping and Kiln Wash Instructions

As you load any kiln, examine the shelves and furniture carefully. Loose, flaky shelf wash should be scraped off shelves with a sturdy metal scraper or a heavy wire brush. Always wear safety glasses or a face shield and a good dust mask when scraping, brushing or grinding shelves, and if possible do the work outdoors. If there is a serious accumulation of glaze residue it must be chipped or ground off before the shelf or furniture is used. Minor glaze drips can be chipped off with hammer and chisel. More serious glaze runs must be ground off. Never chip or grind shelves while they are resting on any hard, unyielding surface—always place them on a cushioning bed of cloth or foam rubber. In a pinch, a bed of sand makes a good support. When chipping glaze accumulations with a chisel, never hold the chisel vertically against the shelf. Always sharpen the chisel so that only one edge is beveled, and hold the flat edge against the kiln shelf, so that the force is parallel to the shelf, against the glaze accumulation as shown in figure 1.

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If the shelf needs to be ground, a standard angle grinder is ideal for the task. For most studio needs, a 4½ inch angle grinder is very manageable and effective. For commercial use, a heavy-duty 7 inch angle grinder is recommended. Always select a grinder with a 4 1/2-inch spindle with 11 threads per inch that will accept all the standard accessories.


Figure 1
Figure 1

For light grinding, fiberglass reinforced grinding disks work fine. For heavier grinding and for leveling irregular shelves, use a masonry-duty diamond cup wheel or silicon carbide cup wheel. For grinding the edges or surfaces of kiln posts an ordinary motorized bench grinder works best. Make sure to keep the ends of your kiln posts very flat to minimize wobble within the set. When unloading a kiln, note which shelves and furniture need cleaning and/or recoating with shelf wash and take care of this routine maintenance right away. In any group or academic studio where a variety of people use the kilns, each user should do all kiln cleanup and shelf/furniture maintenance immediately after unloading the kiln. If there are no glaze runs and the shelf wash is not flaking, you don’t need to do anything to the shelves before the next firing.

If you do need to chip and/or grind glaze or scrape flaky shelf wash from the surface, recoat the shelves with an appropriate shelf wash. A common kiln wash for gas and electric oxidation or reduction kilns is 50% kaolin and 50% flint, but that mixture must never be used in salt, soda, and wood firing. For those processes, use 40% kaolin, 10% ball clay, and 50% alumina hydrate. Mix kiln wash to a thick creamy consistency and apply with a wide brush or paint roller. In some cases you may wish to build up successive coats, especially in any situation where significant glaze runs are fairly common.

In all cases, avoid getting kiln wash on the edges of the shelves where it can flake off in the firing and fall on glaze wares below. A shelf wash of 90% alumina and 10% kaolin works well if you plan to periodically flip your shelves.

Wadding is always used in salt, soda, and wood firings under the ware and on every contact surface between kiln floor and posts, between multiple posts, and between posts and shelves to keep them from glazing themselves together. Wadding is made from the same recipe as shelf wash (40% kaolin, 10% ball clay, and 50% alumina hydrate), mixed to the consistency of plastic clay. For wood firing add a liberal amount of fine sawdust to the mix.

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Crazy Beautiful Crazing: Uncovering the Mysteries of Snowflake Crackle Glazes https://ceramicartsnetwork.org/daily/ceramic-glaze-recipes/mid-range-glaze-recipes/crazy-beautiful-crazing-uncovering-the-mysteries-of-snowflake-crackle-glazes/ https://ceramicartsnetwork.org/daily/ceramic-glaze-recipes/mid-range-glaze-recipes/crazy-beautiful-crazing-uncovering-the-mysteries-of-snowflake-crackle-glazes/#comments Wed, 16 Aug 2017 12:52:50 +0000 https://ceramicartsnetwork.org/daily/ceramic-glaze-recipes/mid-range-glaze-recipes/crazy-beautiful-crazing-uncovering-the-mysteries-of-snowflake-crackle-glazes/ I have been messing around with crazing as a deliberate decorative effect lately. Though it is technically a glaze defect, crazed surfaces can actually be quite beautiful and I have  

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I have been messing around with crazing as a deliberate decorative effect lately. Though it is technically a glaze defect, crazed surfaces can actually be quite beautiful and I have really been enjoying the depth that crackling can create.

But the crackle surfaces I have been creating pale in comparison to the Snowflake Crackle glazes John Britt writes about in the November 2011 issue of Ceramics Monthly. As you can see here, these crackled surfaces are pretty spectacular! Today, I am giving you all a sneak peek at that article, which includes lots of snowflake crackle glaze recipes! – Jennifer Poellot Harnetty, editor.


Side view of cracked bowl showing thickness of fired glaze versus the thickness of the clay body. Glaze thickness is between 1/8 and 3/32 of an inch thick after being fired.

I only had a brief glimpse of this glaze some 15 years ago in a museum gift shop. It was on a little Sake set in a traditional Japanese wooden box. It was glazed with the most beautiful crackle glaze — not the usual crackle glaze that is common in Raku.

It had a conchoidal fracture with the crazes layered on themselves like a stack of books that had slid over.

Only later did I find out that this glaze was called Snowflake Crackle; actually, it has many names (Snowflake Crackle, Fish Scale Crackle, Ice Crackle, Ice-like Crazing, and Tortoise Shell Crackle), which is generally a sign of how much people like something.

Regardless of what you call it, it’s a crazed glaze that is applied so thick that the fractures run not just vertically but horizontally. These crackle patterns can be large or small, and they are distinct hexagonal shapes. When they are large, it is easy to see why it is sometimes called Tortoise Shell Crackle. It is often said that, if you don’t like it, you call it crazing; if you like it, you call it crackle.

Crazing is often thought of as a glaze defect, but as Nigel Wood describes in his book Chinese Glazes, the Song dynasty potters are thought to be the first to treat crazing as a decorative effect. Commonly called Guan (Kuan) Crackle, the Ru, Guan and Ge ware were all beautiful examples of crazing as a decorative technique. In a specifically beautiful type called “iron wire and golden threads,” or “golden floss and iron threads,” the larger cracks, or primary cracks, were stained black while the pots were still hot. The smaller, secondary cracks developed over months or years as the delayed crazing occurred, leaving them brown.

Crazing

Almost everything (except rubber and ice) will expand when heated and contract when cooled. When a clay body and a glaze are fired on a pot, they fuse together. As they cool, if the glaze contracts more than the clay body, it cracks or crazes. If the opposite occurs and the clay body contracts more than the glaze, the result will be shivering, where the glaze will actually pop off of the pot. But if there is just the right amount of compression between a clay body and a glaze, it adds strength to the piece.

Crazing is usually thought of as a glaze defect because the piece can be approximately 75 % weaker than its uncrazed counterpart. It is also thought that the craze lines can harbor germs or bacteria. For these reasons, dinnerware suppliers like to provide uncrazed ware.

Snowflake crackle is the most extreme kind of crazing, where the glaze is applied so thick and the fit with the body is just right so that the crackles appear to lay on top of one other. The glaze can be twice as thick as the body, just like during the Song dynasty. According to Nigel Wood, in order to get the glaze thick enough, Song Dynasty potters often bisque fired pieces between glaze coats.

Detail of a bowl with 1234 Glaze on Orangestone clay, fired to cone 10 in reduction.

A crazing pattern is always the result of the relationship/marriage between the expansion and subsequent contraction (governed by the coefficient of thermal expansion, or CTE) of a clay body and a glaze. By knowing a little about the CTE of oxides, you can easily control the crackle pattern in glazes to create any range of crazing from very small to very large crackles. Since a glaze is a collection of oxides with a variety of CTEs, knowing that sodium oxide has a high CTE and magnesium oxide has a low CTE allows you to control the overall CTE of the glaze by adding one or the other.

As a glass, silica has a low CTE (it is amorphous), but as a crystal, it has a high CTE. So adding silica to a glaze can lower its CTE, because the silica melts to its glassy state. While adding silica to the clay body (where it remains a crystal) can increase its CTE. It is important to keep the firing cone consistent as heating the piece a cone higher will result in melting more of the silica in the body to glass, thus lowering its CTE. Similarly, firing to a lower cone will melt less of the silica in the body giving it a higher CTE. The time and temperature of the firing is extremely important to the CTE of the clay body and thus to the crazing pattern.

Since seeing this glaze in the museum store, I tried many potential recipes with only moderate success. Since I couldn’t get anyone to share their recipe with me, and I had no understanding of the principles of how to achieve this effect, I postponed my search, but in the back of my mind I remembered this beautiful glaze.

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werwet

The uneven stress of glazing only the inside or only the outside of a piece can cause it to shatter

Fast forward about fifteen years to a workshop I was giving last year. I assigned a student a series of tests to improve a magnesium crawling glaze (a.k.a. reticulated glaze) that she was working on in cone 6 oxidation:

SDSU CRAWL/BEADS – Cone 6

Magnesium Carbonate 25%

Nepheline Syenite 70%

OM-4 Ball Clay 5%

Total 100%

twert

Snowflake Bowl, 5 in. (13 cm) in diameter, wheel-thrown Brownstone Clay, with Snowflake Crackle Glaze #8, fired to cone 6 in an electric kiln.

I had her make up the glaze without the magnesium carbonate and then add it back in 5% increments up to 40%. She then dipped tiles of stoneware, dark stoneware, and porcelain. Fortunately, one of the clay bodies she was using was a very dark low-fire Redart body that she liked to fire to cone 6 (it is rated from cone 05–6). When the tiles came out of the firing, my eye went immediately to the 5% magnesium carbonate test on the dark body; it was Snowflake Crackle! What a stroke of luck. Unfortunately, I didn’t care about her reticulated surface anymore, as I was so excited about this crackle pattern.

Testing

When I returned home, I tried the glaze on a variety of store-bought cone 6 clays. The best, in terms of CTE, were Highwater’s Earthen Red and Brownstone at cone 6, and Orangestone at cone 10. There very well may be others that work, but these were the best of those I tested.

Since potters today generally buy premixed clay bodies rather than making their own, changes in CTE are usually made to the glaze rather than the clay body. This glaze crawled a bit, so I decided to remove the magnesium carbonate (because it has such a high shrinkage) and substituted talc.

While I was analyzing the glaze in Insight (a glaze software program), I decided to look at the CTE numbers, which were around 8.59 (Insight CTE). I then constructed about four glazes with similar CTEs, between 8.59 and 8.70. I came up with several nice glazes this way, but I also tested the original recipe with a simple progression of Ferro frit 3124, just to see if it would melt a bit more. The result was a nice transparent Snowflake Crackle with 8% frit.

Color

The first thing I noticed when I did color test with the usual colorants and opacifiers (copper carbonate, red iron oxide, chrome oxide, stains, zircopax plus, etc.) was that, as the color improved, the crazing ceased. This was because all oxides have expansion/contraction rates and adding them changed the CTE of the glaze enough to stop the crackle effect. I ran more tests with very low levels of colorants (under 1%), which kept the crazing yet still produced a nice color.

Mixing and Application Notes

• These glazes contain high amounts of Nepheline Syenite, which is partially soluble, so the glaze slop can easily deflocculate affecting application thickness. Adding Epsom salts corrects the problem. Mix to a specific gravity of approximately 155–160.

• These glazes must be applied thick, between an eighth and a quarter of an inch (3–6 mm).

• Snowflake crackle is not limited to cone 6; that is just the first temperature where I discovered it. In the cone 10 versions, watch for the flocculating effect of bone ash. You may need to add a deflocculant (sodium silicate), otherwise the glazes can flake off before you get the pots into the kiln. If they don’t flake off, they usually crawl badly during the firing.

• Be sure to wait a couple of days after firing for the crazing to complete enough to see it (this is called delayed crazing.) One load came out and I thought they were unsuccessful, with no crazing. I went away for a long weekend and, to my surprise, when I came back they were all crazed nicely with the Snowflake Crackle effect.

• These glazes are not recommended for functional work as you can often feel the crazing patterns with your hand.

• Glazing only one side of a bowl, either inside only or outside only, will cause the bowl to shatter from unequal tension. After the pots are fired, the glaze sometimes thins on the rim and you can see the brown clay body. This is called “brown mouth” or “purple rim and iron foot” (the glazed rim will reoxidize differently from the unglazed foot).

• The crackle works best on the inside of bowls as the concave interior accentuates the crackle effect.

After arriving at the cone 6 recipes, I started testing for cone 10. I took four separate recipes and tested each on four clay bodies. But before I threw them out, I poured each cup into another to get a blended test. I poured cup 1 into cup 3 (Glaze Snow Flake Crackle 13), then I poured in cup 2 (which became Ice, Ice Baby) and finally I poured all three together for the glaze Snow Flake Crackle 1234. As it turned out, none of the original four recipes worked very well, but the three blends were great! (That is a super secret way to get more mileage out of your tests!)


**First published in 2011

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A Plethora of Purple: Glaze Recipes for Earthenware, Stoneware and Porcelain https://ceramicartsnetwork.org/daily/ceramic-glaze-recipes/low-fire-glaze-recipes/112111-a-plethora-of-purple-glaze-recipes-for-earthenware-stoneware-and-porcelain/ https://ceramicartsnetwork.org/daily/ceramic-glaze-recipes/low-fire-glaze-recipes/112111-a-plethora-of-purple-glaze-recipes-for-earthenware-stoneware-and-porcelain/#comments Wed, 16 Aug 2017 10:00:36 +0000 https://ceramicartsnetwork.org/daily/ceramic-glaze-recipes/low-fire-glaze-recipes/112111-a-plethora-of-purple-glaze-recipes-for-earthenware-stoneware-and-porcelain/ Purple is one of my favorite colors. From pale lavender to deep eggplant there are so many gorgeous purple hues. Yet, browsing through the Ceramic Arts Daily archives, I noticed  

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Purple is one of my favorite colors. From pale lavender to deep eggplant there are so many gorgeous purple hues. Yet, browsing through the Ceramic Arts Daily archives, I noticed that we don’t have a whole lot of purple glaze recipes posted. Well, today I am going to remedy that situation.

In today’s post, an excerpt from Linda Bloomfield’s Colour in Glazes, I am presenting a plethora of purple glazes – from low fire earthenware recipes to mid-range and high fire stoneware and porcelain, there should be something for everyone interested in making some purple pottery! – Jennifer Poellot Harnetty, editor.


Several Great Recipes for Purple Glazes

Purple can be made by adding a small amount of cobalt to a chrome-pink tin glaze, or by adding manganese and cobalt to an alkaline glaze. Cobalt turns lavender-blue in magnesium glazes (containing talc or dolomite), and an intense purple-blue can be obtained in high-cobalt barium matt glazes. Purple can also be obtained from copper oxide in barium matt earthenware glazes. Manganese dioxide will produce plum purples, particularly with cobalt in high-alkaline, low-alumina glazes. Neodymium oxide produces a pale violet in alkaline glazes, particularly those containing barium or lithium, which increase the solubility of the neodymium. Nickel gives dark aubergine purple in barium glazes. If cobalt or rutile is added to a copper red glaze, purple can be obtained in reduction.


Color your world!!

Order Linda Bloomfield’s Colour in Glazes for the lowdown on creating colorful pottery!


**First published in March 2014

Purple Glaze Recipes – Cone 04 Earthenware (above)

Purple Glaze Recipes – Cone 8 – 9 Stoneware (above)

Purple Glaze Recipes – Cone 6 – 8 Porcelain, Oxidation (below)


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Combining Wheel Techniques and Handbuilding Pottery for Great Results https://ceramicartsnetwork.org/daily/pottery-making-techniques/handbuilding-techniques/combining-wheel-techniques-handbuilding-pottery-great-results/ https://ceramicartsnetwork.org/daily/pottery-making-techniques/handbuilding-techniques/combining-wheel-techniques-handbuilding-pottery-great-results/#respond Wed, 16 Aug 2017 09:00:28 +0000 https://ceramicartsnetwork.org/?p=164822 When exploring ideas for hand building pottery forms using smaller wheel thrown parts, Ronan Kyle Peterson discovered something pretty cool: Cutting a wheel-thrown piece in half and reassembling it, can  

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Yonic Double Seed Server, 21 in. (53 cm) in length, red earthenware clay, with layered slips, terra sigillatas, and glazes, fired to cone 03 in an electric kiln, 2017. Photos: Kathryn Gremley. Courtesy of Penland Gallery.

When exploring ideas for hand building pottery forms using smaller wheel thrown parts, Ronan Kyle Peterson discovered something pretty cool: Cutting a wheel-thrown piece in half and reassembling it, can double the length of the piece! In today’s post, Ronan explains how he cuts a wheel-thrown cone in half, reassembles it, and ends up with a good-sized (and good looking!) serving dish. –Jennifer Poellot Harnetty, editor.

P.S. Learn how Ronan Kyle Peterson uses terra sigillata, slips, and glazes after handbuilidng his pieces to create his finished surfaces in the September 2017 issue of Ceramics Monthly. You’ll find Peterson’s recipes in the issue as well!

 


 

Handbuilding Pottery Using Wheel Thrown Parts

I take 4 pounds of red earthenware clay, and on a plastic bat, throw a bottomless cylinder into a peaked closed form, shaped like a bullet, and cut the form free from the bat with a cut-off wire.

I let the closed form dry overnight uncovered, except for a small piece of plastic over the top to prevent it from drying too much. The plastic bat prevents the form from drying too much from underneath.

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Altering the Form with Handbuilding Techniques

Using a ruler or straight edge, I roll a straight mark up the side of the form (1). This line guides me as I take a fettling knife and slice the form in half (2). I lay down the form horizontally on a rectangular board, cut-side down (3), and slip and score the edges that were the bottom when the piece was upright. I slide the slipped and scored edges together and wiggle them to help the score marks grab on and hold onto one another. I blend the seam together with my fingers (4) and then smooth the joint with a flexible rib.

1 Use a ruler to help make a straight cut on the closed-off cylinder.

2 Using a fettling knife, cut the thrown form in half.

3 Lay both halves cut-side down on a long board.

After joining and smoothing the seam, I flip the form over with the curved side down and the cut side up. I take pieces of foam and wedge them in place to support the upward curve of the ends of the joined form. I pinch and blend the seam inside of the form, making sure to compress and join the seam thoroughly (5). I like to leave a raised bead of clay where the seam meets, which hints at seed chambers within a nutty shell.

Handbuilding a Foot

I take a sheet of plastic that is much larger than my rectangular board, lay it down on the board and then flip the form back over and place it (cut-side down) onto the plastic. The plastic helps keep the cut edge moist, so I can add a rim later. I cover the form with plastic overnight and then uncover it the next morning. After the piece dries to a stiff leather hard, I roll out a thick coil and form it into an oval that fits the center of the curved form (6). I miter cut the ends of the coil for a stronger joint. After getting the coil centered and situated, I use a needle tool to trace the outline of the coil. I remove the coil, slip and score the body, and score the bottom of the soft coil. I then join the scored surfaces, blend the seam (7), and pinch a tall, oval foot.

4 Use your fingers and a flexible rib to blend the outside seam together.

5 Pinch, then smooth the inner seam with a flexible rib, leaving a ridge at the joint to reference seed chambers in a nutty shell.

6 Roll out a thick coil for the foot.

7 Blend the seam into the body of the form.

After the foot has stiffened, I cut a seagull-shaped notch out of the center of the longer side of the oval foot (8), and smooth the cut edges. The wide-to-tapered, curved notch fits the sensibilities of my piece, with its floral and plant life references. A V-shaped cut or U-shaped cut would not have the same reference. The shadow inside the cutout draws the viewer’s eye to it.

Handbuilding a Rim and Handles

I flip the form over onto the foot, place it on a bat or board, and level the top by pushing gently on the form. I roll out two thick coils that are longer than each side of the rim, using a string to help get the right measurement. I lay the coils on the rim, (9) place the ends one on top of the other, and cut through both coils at the same angle to get a mitered cut. I score the coils, lay them off to the side, slip and score the top cut edge of the form, then attach the two pieces together. Working with the piece on a banding wheel, I take the coils and place them firmly on the scored rim of the piece and pinch and blend the seam. After joining the seam and blending the connection, I slowly start pinching the thick coil up (10), trying to maintain an inward motion so that the rim doesn’t spread out as I pinch it into a taller wall.

8 Cut a curved notch out of the foot.

9 Lay out thick coils on the rim, slip and score both the rim and coils.

10 Pinch and compress the coil to the rim of the form, then pinch the coil in to make a tall rim.

After the wall sets up, I make two puffy seed-pod handles out of pinch pots, one for each point of the elliptical form. These hint at functioning handles, but I use them to continue the line of the rim and draw the viewer’s eye into the space around the form. I trace their outline, slip and score the pod and its resting place, then attach and add texture. I cover the whole piece overnight with plastic and let all the parts equalize in moisture to prepare for slip decoration the next day.

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Stay Put Glaze! A Great Tip for Transporting Glazed Pots https://ceramicartsnetwork.org/daily/pottery-making-techniques/ceramic-glazing-techniques/stay-put-glaze-a-great-tip-for-transporting-glazed-pots/ https://ceramicartsnetwork.org/daily/pottery-making-techniques/ceramic-glazing-techniques/stay-put-glaze-a-great-tip-for-transporting-glazed-pots/#comments Wed, 16 Aug 2017 08:01:55 +0000 https://ceramicartsnetwork.org/daily/pottery-making-techniques/ceramic-glazing-techniques/stay-put-glaze-a-great-tip-for-transporting-glazed-pots/ Because kilns can have a hefty price tag, many potters just starting out rely on others to fire their work. It can be tricky transporting greenware around and resourceful potters  

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Because kilns can have a hefty price tag, many potters just starting out rely on others to fire their work. It can be tricky transporting greenware around and resourceful potters have come up with ingenious ways to protect their work (here are two great ideas from the archives). As if ceramic glazing wasn’t challenging enough, transporting glaze ware can also be challenging because the fragile unfired glaze surface can be easily dinged or chipped. But things just got a little easier, thanks to Chanda Zea.

In this post, Chanda shares a secret she picked up during her time as a ceramics undergraduate student at Buffalo State College. So no more need to worry when your ceramic glazing needs to happen on the go! – Jennifer Poellot Harnetty, editor.


 How to Transport Glaze Ware Safely

by Chanda Zea

In the summer of 2013, I did a one-month residency at Red Lodge Clay Center in Montana with four other artists. As we have all experienced, time goes by really fast when you’re making, bisque firing, glazing, and firing lots of new work. Inevitably, we make more than we can finish, and are faced with the dilemma of what to do with the glazed pottery we didn’t fit in the kiln.

Tips from your peers!
Ceramic artists are always coming up with innovative, clever ways to solve problems in the studio and Ceramics Monthly shares the best tips in every issue. In addition to the great studio visits, techniques, new work, glaze recipes, and the fascinating stories of ceramic artists living the dream, your next time and money saving tip could be in the next issue.
Learn more!
1] Common spray starch available at the local grocery store. 2] Apply underglaze pencil or glaze and let dry. Using a banding wheel, apply an even coat of spray starch.

1] Common spray starch available at the local grocery store. 2] Apply underglaze pencil or glaze and let dry. Using a banding wheel, apply an even coat of spray starch.

When our group ran into this issue, I suggested using a trick I had picked up back in my undergraduate days at Buffalo State College. At that time I was applying multiple glazes to each pot using a spray gun, and was dismayed at how powdery the freshly sprayed glaze was. Sprayed ceramic glazes tend to be very porous, powdery, and easy to rub off your pots. Some of the glazes I was using were so sensitive that fingerprints from where I handled the pot would show up after the cone 10 firing.

One of the other students suggested using spray starch (1)—commonly used for ironing, and available at any grocery store. The spray starch, when applied in an even coat and allowed to dry, creates a hard surface that protects your glaze (2–3), but burns off in the kiln, leaving no trace behind (4). (Another variation on this trick is to use liquid starch, also available in the laundry section of your local grocery store, and mix it into your bucket of glaze—this will get moldy so mix it in small batches. If it does mold, just skim the mold off and stir well. Any remaining small traces of mold will burn out in the kiln.)

Preventing Smearing of Underglaze Pencils

stay-put-glaze-ware-2

Spray starch was used on this pot to keep the underglaze pencil lines from smearing before it was glazed then fired.

More recently, I started using underglaze pencils to add some line work to my functional pieces, but was having a hard time with the powdery pencil marks easily smearing. I decided to experiment on one of my class demo pots, and see if the spray starch would also work under the glaze, fixing the pencil in place so I could paint on clear glaze with worrying about smearing. It worked like a charm. The pencil didn’t smear, and the starch burned off in the kiln, with no side effects (5).

Send your tip and tool ideas, along with plenty of images, to editorial@ceramicsmonthly.org. If we use your idea, you’ll receive a complimentary one-year subscription to CM!

**First published in December 2014

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Making Multiples: Using Templates to Throw Uniform Shapes on the Pottery Wheel https://ceramicartsnetwork.org/daily/clay-tools/making-clay-tools/making-multiples-using-templates-to-throw-uniform-shapes-on-the-pottery-wheel/ https://ceramicartsnetwork.org/daily/clay-tools/making-clay-tools/making-multiples-using-templates-to-throw-uniform-shapes-on-the-pottery-wheel/#comments Wed, 16 Aug 2017 08:00:27 +0000 https://ceramicartsnetwork.org/daily/ceramic-glaze-recipes/mid-range-glaze-recipes/making-multiples-using-templates-to-throw-uniform-shapes-on-the-pottery-wheel/ I think many beginning potters start out with the goal of making perfect sets of bowls or mugs, but quickly realize that it isn’t that easy to make exact duplicates  

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I think many beginning potters start out with the goal of making perfect sets of bowls or mugs, but quickly realize that it isn’t that easy to make exact duplicates on the pottery wheel. It can be argued that this is precisely the charm of hand-made objects–that they are not perfect. If you want perfect, you can get factory-made pottery at your local big box store.

But, if you still can’t let go of the idea of making exact sets, you might want to try using a throwing template. Today, potter Bill Schran explains how he makes and uses templates to throw multiples on the pottery wheel. Enjoy! – Jennifer Poellot Harnetty, editor.


 

When my beginning wheel-throwing pottery students have developed a sufficient facility with clay, they’re assigned the project of creating a set of four matching cups. Though I’ve demonstrated to students how to measure their forms using calipers and other devices, I continue to observe them experiencing difficulties. In an effort to overcome this stumbling block, I decided to show a technique that has been successfully used by students in my beginning handbuilding class.

This technique involves the use of templates to repeatedly create an even, symmetrical form. In the coil-building exercise, the template is positioned abutting the pot as coils are added, making certain the pot conforms to the profile of the template. The template is then used as a rib to scrape the surface of the pot as it is rotated, creating a smooth, uniform surface.

Making a Throwing Template
To incorporate this technique into wheel throwing, I began with testing of various materials that might serve the function of a template. The result of these tests proved to be sheet plastic, a durable material that can easily be cut and shaped. Searching through scraps available at local glass supply and repair shops, I found pieces of 1/4 in. and 3/16 in. sheets that could be cut with a power saw and handsaw and could be readily shaped into the desired profiles. The edges can then be smoothed with fine sandpaper. This process can also be used to produce templates with more complicated and compound profiles with relative ease. The image to the right shows an assortment of throwing templates made of sheet plastic.

Creating the Form

Wheel throwing templates used to throw vase forms.

To use a template, as in the wheel-throwing project for the set of cups, prepare several balls of clay weighing between ¾–1 lb. each. Throw a basic wide cylinder. Check the interior diameter, height and width of this basic form with calipers.

Tip: Make a template for the basic cylinder form as well as the finished piece. The first template, showing the right width and shape of the ideal starting cylinder, can help you get the right basic shape.

Once you have your cylinder ready, lubricate the interior of the pot, but do not lubricate the outside. Avoiding excess water results in a stronger form that can better withstand manipulation and alteration when using the template.

Position the bottom of the template so that it’s just touching the bottom of the pot and rests on the wheel head. The template should contact the wheel but should not be pressed against it. Hold the template at approximately a 45° angle, abutting the rotating clay, such that the clay moves away from the edge of the template. The template should not be held at a 90° angle to the pot as this may lead to inadvertently shifting the template into the movement of the clay.

Wheel throwing templates used to throw mug forms.

Wheel throwing templates used to throw mug forms.

The fingers of the interior hand slowly move up, pushing the clay out to the curve of the template. As the pot widens, the hand must move up along the interior of the form more slowly so that it remains symmetrical. After reaching the top, the profile of the pot and template should be compared. If the pot does not match the template, move the fingers of the interior hand down from the top to the bottom, pushing out where necessary, to conform to the profile of the template. This is often necessary for shapes with wider diameters. Refine the rim with a sponge or chamois and the cup is complete.

Large or Complex Forms

Templates are also useful in creating larger pots, particularly bottle shapes. The profile template provides a method to quickly create multiples of the same form, but also the opportunity to explore changes to certain areas, such as the neck and rim. The process of working with larger forms follows the same steps as you would for cups, except the neck and rim are made without the template, after the basic shape has been defined.

To get started, make another cylindrical shaped pot, leaving the top portions of the wall, including the rim, thicker than the rest of the pot. Position the template and push the clay out to conform to the shape, moving fingers on the interior up and down as necessary. After creating the desired curve, pull up the upper portion of the wall to thin it out and narrow it in using a collaring movement. Note: It is very important to continue moving your hands up while collaring in to maintain a curve or arch in the shape of the wall. A wall that becomes too horizontal or flat during the collaring and thinning process may be pulled down by gravity and collapse. In order to collar in the pot, use the middle fingers and thumbs to constrict the neck. As you create the neck, pressing down on the rim with the first finger of the right hand helps to maintain a level top.

Use a flexible rib after each collaring process to refine the shape and maintain the desired curve. Using the rib also removes excess water and compresses the clay. After narrowing the diameter of the pot, the wall has been thickened and can now be pulled up thinner. As the top becomes too narrow to insert a sponge to remove lubricating water from the interior, switch to using slurry to lubricate the clay instead. This allows your fingers and tools to continue shaping the clay without building up excess torque that might twist or tear the clay wall. Using slurry on the exterior, instead of water, provides a stronger clay wall.

**First published in 2011

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Using Colored Clay and Etching Techniques to Explore Patterns and Textures on Functional Pottery https://ceramicartsnetwork.org/daily/ceramic-supplies/pottery-clay/using-colored-clay-and-etching-techniques-to-explore-patterns-and-textures-on-functional-pottery/ https://ceramicartsnetwork.org/daily/ceramic-supplies/pottery-clay/using-colored-clay-and-etching-techniques-to-explore-patterns-and-textures-on-functional-pottery/#comments Tue, 15 Aug 2017 09:00:31 +0000 https://ceramicartsnetwork.org/daily/ceramic-supplies/pottery-clay/using-colored-clay-and-etching-techniques-to-explore-patterns-and-textures-on-functional-pottery/ Debra Oliva uses different colored clays and etches surface designs to add depth to her pots. The results look like a Samurai warrior's suit of armor.  

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Debra Oliva’s work is inspired by a Samurai warrior’s suit of armor, which she saw on a visit to a museum. Impressed by the combinations of grays, blacks, and browns, as well as the patterns, textures, and fine details, Debra knew she had to work these elements into her clay work.

She does this by throwing in sections with different colored clays, painstakingly etching surface designs, and adding more color with underglazes and terra sig. In today’s post, an excerpt from the Ceramics Monthly archives, Debra explains her process. – Jennifer Poellot Harnetty, editor.


During a visit to a museum I discovered a Samurai warrior’s suit of armor. It was an amazing combination of woven fabrics, leather, and metal. I was taken by the subtle combinations of grays, blacks, and browns, and the relationships between the many patterns and textures, the fine details, and impeccable craftsmanship. This garment presented a clarifying moment that helped me identify the aesthetic I would follow, the elements that are important to me, and where I might look for inspiration.

1 Each color section is thrown separately. While still attached to the bat, the next section is inverted and placed on the previous section rim to rim and then cut free from the bat.

2 The sections are sealed together by throwing downward from the upper section toward the lower section without disturbing the seam.

3 After all the sections are added, final throwing and refining of the form is completed. The base of the work is trimmed in the upright position. Later it will be inverted to trim the foot.

 

Fabrication

When developing new forms, I consider the proportions of the color sections and the placement of decorative elements. Next, I make a rough drawing as a guide and go to the wheel to make a few prototypes to work out the form and get comfortable making the piece. Estimating the amount of clay I will need, I throw the bottom section and finish it with a level rim. I take a measurement of the rim diameter and set it aside while I throw the next section.

I begin the etching process at the leather-hard stage, working on a small section while keeping the rest of the piece damp and covered. My etching tools include a pin tool, pencils, scoring tools, drill bits, and serrated ribs that I cut into small pieces and insert into X-Acto blade handles (4).

4 Lines are incised using a pin tool and solid areas are etched with a tool made from pieces of serrated ribs inserted into X-Acto blade handles.

For the line work, I begin by dividing the space, making a small mark where a line will be drawn. With the piece spinning slowly on the wheel, I incise horizontal lines using a pin tool. Then I incise vertical and diagonal lines by eye. If there are elements to transfer, I use a sharp pencil and a light touch, to transfer designs from tracing paper to the leather-hard ware. I then retrace the patterns to incise them more deeply into the surface. To etch pattern areas, I use my home-made tools.

Firing and Finishing After bisque firing, I lightly sand the piece with fine grit sandpaper to remove any burrs that may still be remaining from the etching process and the dust is wiped off. I brush terra sigillata or commercial underglaze into the incised lines or areas and sponge the excess away (5). I glaze the interior with a black or clear glaze and fire the work to cone 8 in an electric kiln. After the glaze firing, I apply a durable, food-safe wax product to the unglazed exterior and buff it to a soft sheen with a shoe shine brush.

5 After bisque firing, terra sigillata or underglaze is painted over the incised areas and the excess is sponged away.

Working with clays colored with varying amounts of oxides and stains can be challenging as the color sections dry and flux differently. This may create tension between the sections, which could result in warped rims, often only becoming apparent after the final firing. These pieces are unacceptable to me; however, because of this uncertainty and inevitable loss, successful pieces are that much more rewarding.

Check out Curt Benzle’s video clip Tips and Techniques for Making your Own Colored Clay for a way to mix your own colored clays using one clay body as a base, to avoid loss due to different shrinkage rates between the clays.


**First published in 2012

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